Maximal subfields in division algebras generated by images of polynomials
摘要
We investigate conditions on an element in a finite-dimensional division ring over its center such that the associated simple extension over the center is a maximal subfield. Specifically, we prove that a simple subfield extension by a value of either a multilinear polynomial in non-commuting variables or a free group-word at a suitable substitution, is a maximal subfield. This is interesting even in the case of characteristic zero, where any finite algebraic field extension is simple.